Comments:

As the resident GURPS fanboy - sorry, obsessive GURPS fanboy - I will just make sure I'm the one to point out that this is a somewhat common occurrence in that system. Side effect of a potentially complicated system that gives you so many options. XP

Sticking to a specific example... well I'm drawing a blank.

I recall as a general experience I recall my high school/early college group often hitting a puzzle that the GM (and not always the same GM >.>) assumed we'd get easily in real life and we would be clueless. To make this mildly amusing to you all (and on topic), if not the whole time then pretty quickly whoever was being the GM for that campaign would catch on and make sure a PC had a relevant skill to roll against for clues or (if we took way too long) to just solve it outright...

...but we were often so clueless about the puzzle we didn't realize what skill we ought to be rolling against. Makes it tricky to know which character ought to be making the roll. Sure you can go with the smart guy but that is too obvious. ;)

Humans are cattle to be inhabited by the demons. You might be lucky enough to be possessed by a demon who doesn't enjoy torture, murder and tomenting others in every way imaginable.

However, you would never again have full control of your own body. Being possessed, however, makes your body stonger, faster, and more resilient.

Add to that the stargate style squabbling between the demon factions, and it was pretty cool. I miss my old writings. I lost so much when my old hard drive died. There was a short, and the drive was fried.